The SMACool project consists of nine interconnected work packages (WPs). WP1 addresses project organization, while WP8 and WP9 focus on networking within the portfolio and all communication, dissemination, and exploitation activities. WP2 serves as the scientific starting point and foundation of the project, as all consortium members will develop the system approach, concept, and architecture together. The results from WP2 are then applied in WPs 3, 4, 5, and 6, which cover four different research areas: materials, simulation, drive system development, and system device realization. All four WPs have strong interactions with each other and are supported by WP7, which handles experimental characterization and validation across all project areas and phases.
Initial evaluations of various elastocaloric device concepts were conducted numerically, also as part of WP4. The primary objective was to define operating conditions capable of delivering cooling power of at least 500 W, with a temperature span of 15 K, and a maximized Coefficient of Performance (COP).
Next task was to develop a geometry for a compressively loaded elastocaloric structure (regenerator) that facilitates efficient heat transfer while preventing structural buckling during compression. Preliminary simulations have been conducted to assess the buckling behavior of several targeted designs under compressive loading with promising results, which lead to experimental verification in the next step.
For the solid-state refrigerant material, work has focused on the development of Exergyn’s proprietary NiTi-based shape memory alloy, specifically tailored for elastocaloric operation. Testing shows the material to be structurally and functionally stable, with sharp transformation behavior and low hysteresis under compression. In parallel, a second proprietary melting route is being developed. This aims to reduce the mechanical and thermal stabilization typically needed during early cycling, so the material reaches steady high efficiency performance much faster. The expectation is that this will lower the work input on initial actuation and improve energy efficiency (COP). Internal trials are in progress, with early results showing promise. Material production has been scaled from small laboratory quantities to ingots exceeding 100 g. This provides enough material for detailed testing under realistic load and temperature conditions.
For the drive system, two mechanisms were investigated for converting rotational motion into linear compression for SMA elements, which are currently object of protection measures.
To precisely evaluate system performance, a laboratory testing environment for HVAC devices has been developed and is being realized. This test setup consists of two isolated, temperature-controlled chambers that simulate outdoor (seasonal) and indoor (room with thermal load) air for the device under test. The chamber temperatures are controlled by commercially available, custom-adapted temperature control units. To evaluate the device’s performance, flow rates and temperatures at the inlets and outlets of the chambers are measured to calculate the thermal power. Additional measurement of the device’s electrical power consumption enables calculation of the Seasonal Coefficient of Performance (SCOP).
